new engine won't idle
I just had a new engine built for my '97 CVPI. It has coated 10.4:1 forged Probe pistons, Eagle rods, and "GT" cams which spec at 188/198 duration, .510/.540" lift. The heads are nasty stockers, with a valve job and those new 87 lb springs with titanium retainers.
The machinist installed the engine. It seems to run fine at higher RPM, but as at drops down to idle, it doesn't want to stay lit. It has very low vacuum at an idle, but I don't suspect a vacuum leak. The fuel and spark worked flawlessly before the new engine, I have no reason to suspect them now. The computer does give lean codes, however.
We pulled the timing cover off and checked the cam timing using a degree wheel and dial indicator. It seems to be correct.
Is this simply a case of the brain needing to learn to give the engine more fuel at low RPM? I thought being a MAF system, the fuel would still be correct, despite the relatively small changes to the engines tune. We didn't actually drive the car on the road, just ran it in the shop. It seemed to idle so poorly we thought something was wrong. Now, I'm wondering if it's just the idle fuel mixture being incorrect for the new engine...
Has anyone installed a slighlty modified engine before? Does the brain need to be re-programmed? Will it "learn" on its own?
'97 Crown Vic police, rebuilt with 188/198 cams, 10.3:1 CP forged pistons, 80mm F150 Lightning MAF, DR chip, Eagle floating rods, truck dual-row radiator core, clutch fan deleted, new 4R70W mild shift kit, Moog/Edelbrock suspension, 17 X 8 Konig 5.0 wheels, 255/50R-17 BFG KDWS rubber